1. Field of the Invention
The present invention relates to a method of establishing a registered pattern on a metal coil and associated apparatus and, more specifically, it relates to such a system that is adapted for precise control of the pattern so as to facilitate more efficient use of the metal coil in making products therefrom.
2. Description of the Prior Art
It has been known to manufacture products by creating repeated patterns of printed elements on metal coil and, subsequently, severing portions of the metal coil each containing one of the patterns and forming the same into products. Among the many uses for such coils have been the manufacture of packaging and building products such as can end stock and doors, for example.
One of the problems with such coils is that even minor departures from tolerances in the longitudinal direction could have a sufficiently large cumulative effect that an end user may have substantial waste material. An end user having punch presses set up to punch out portions of the coil at predetermined locations can create a defective product as a result. If the predetermined pattern departs from the those locations, the portion of the metal punched out will not contain the full patterned image.
While such punching of patterns from parent stock can be accomplished within tolerances easily when discrete sheets of relatively small lengths are employed, there remains a problem with long coils of metal.